1. Field of the Invention
The function of planetary gear systems is known per se. A sun gear or a sprocket is located at the drive side, which is driven by an engine connected via an engine flange to the planetary gear system. The sprocket transfers its motion to generally three traveling planet gears forming a gear speed, which are arranged on a bearing pin of a planet carrier, with at the drive side the planet carrier being connected in a torque-proof fashion to a sun gear combing the following gear speed with the planet gears of the planet carrier. In case of several gear speeds, the last planet carrier is connected fixed to a drive shaft and ensures this way for the force transmission at the drive side. On the outside, the planet gears travel in a transmission housing with internal teeth, the so-called hollow wheel. Further, the transmission housing is connected to a drive flange at the drive side.
2. Background of the Invention
The current state of knowledge is as follows.
A generic planetary gear system is known from DE 44 25 961 A1, with its planet carrier being produced in one piece as a plastic part comprising a planet carrier plate and the bearing pins rotationally accepting the planet gears. Here, polyamide is suggested as the plastic material. Additionally, according to this document, the planet gears are also produced from plastic.
Further, the bearing pins of this planet carrier of prior art according to DE 44 25 961 A1 are provided with a bead-like reinforcement at their connections at the planet carrier plate.
By such a reinforced embodiment of the planet carrier in the area of the connection of the bearing pin at the planet carrier plate, the torque stress can be increased without here a breakage occurring during operation of the planet carrier or the bearing pin. However, it is disadvantageous here that in the area of this bead-like reinforcement the planet gear placed thereon requires an area-fitting adjustment, resulting in additional expenses for the production of such a planet gear.
A planet gear is known from DE 10 2005 004 488 A1 in which a washer is arranged between a planet gear supported on the bearing pin and the planet carrier, comprising torque-proofing in the form of burling or studs, which engage corresponding recesses and/or elevations in the planet carrier. Such washers serve, on the one hand, to compensate axial forces of the planet gears, which for example develop by helical gearing of the planetary gear system and on the other hand damp oscillations as well as to ensure the supply of lubricant to bearings of the planet gears through recesses in the washers. In this planet gear system of prior art, the construction expense and the assembly expense are very high because on the one hand the production of such washers with burling or studs is expensive and additionally the planet carrier plate must show respective recesses and/or elevations and, on the other hand, the washers are required as additional parts to be assembled in the planetary gear system.
The objective of the invention is therefore to further develop a planetary gear system of the type mentioned at the outset such that the above-mentioned disadvantages are avoided, thus particularly a planetary gear system is provided, which can be produced and assembled in a cost-effective fashion.